Vacuum operated squeegee



Nov. 1, 1966 s. L. HERSH VACUUM OPERATED SQUEEGEE 2 Sheets-Sheet 1 FiledSept. 28, 1964 M ASPIRATOR v I'- lili INVENTOR, sev/woun L. HERSH.

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ATTORNEN Nov. 1, 1966 s. L. HERSH VACUUM OPERATED SQUEEGEE 2Sheets-Sheet 2 Filed Sept. 28, 1964 FIG. 5

INVENTOR. SEYMOUR L. HERSH.

A T TORNE 3 United States Patent 3,281,885 VACUUM OPERATED SQUEEGEESeymour L. Hersh, Freehold, NJL, assignor to the United States ofAmerica as represented by the Secretary of the Army Filed Sept. 28,1964, Ser. No. 399,949 2 Claims. (Cl. -393) The invention describedherein may be manufactured and used by or for the Government forgovernmental purposes, without the payment of any royalty thereon.

This invention relates to a squeegee type drying device for removingsurface adherent liquids from such materials as photographic film orother materials from which surface liquid must be removed.

The invention is particularly directed to a spongelike highly absorbentmeans which is moved along the surface with light pressure to absorb thesurface liquid therefrom by capillary action and to continuously andrapidly remove liquid accumulated in the sponge element thereby tomaintain the sponge in a highly absorbent condition.

The invention may be used to remove liquids from a variety of sheetmaterials and is particularly useful upon material having wettedsurfaces which are soft and sub- 'ect to abrasion such as photographicfilm or paper. It has been common practice to use a soft sponge or somesponge like material which is passed over the material to absorb thesurface liquid. In this technique the liquid quickly loads the sponge tothe point where it fails to function. To restore the sponge the liquidmust be repeatedly squeezed to expel the liquid. This is wasted time andmoreover the sponge functions at its optimum capacity for only a portionof it operating period.

In addition to the sponge various other manual Wiping devices have beenused such as the simple rubber Wiper blade which is not an effectivedevice and fails to protect sensitive surfaces from scratches andabrasions.

In the faster types of squeegee devices the air knife is used. Thisdevice applies a flat jet of high pressure air to the surface. Thistechnique, although effective, requires complex and costly equipment forbest operation.

Another technique is to use a vacuum cleaner type nozzle which is passedover the wetted surface. A large vacuum pump is required for this systemand a tight seal must be maintained between the nozzle and the surfacetreated. This is difficult to accomplish and subjects the surface todamage by the sealing means.

The present invention overcomes the drawbacks of prior techniques andprovides rapid and complete removal of liquid from the treated surfacewithout damage thereto.

The invention is described briefly as follows. The main absorbingcomponent consists of a body of soft resilient sponge which may be thenatural variety or a synthetic type and having a working face forengaging the wetted surface. The sponge is enclosed within a casing ofsuitable material such as plastic or metal. The

casing encloses all but a small portion of the sponge adjacent itsworking face and is made to fit snugly but not tightly in the casing.The upper portion of the casing is provided with an opening within whichis tightly received a tubular fitting to which is attached a flexibletube communicating with a vacuum pumping system. Substan tially thewhole volume of the sponge is thus subjected to the vacuum. Thus whenthe squeegee is lightly moved over the wet surface the capillary actionof the pores in the sponge removes the liquid from the surface. Howeverwhen the liquid enters the sponge it is also acted upon by the vacuumwhich moves the liquid towards the vacuum connection from where itpasses to a draining outlet. In this manner the sponge is continuouslymain- 3,231,885 Patented Nov. 1, 1%66 tained in optimum workingcondition and thus is able to remove the liquid rapidly without stoppingto expel liquid from the sponge.

An important feature of the invention is the effective manner in whichthe applied vacuum is confined to the portion of the sponge in contactwith the workpiece. By so confining the vacuum the optimum effectivenessof the device :is achieved and maintained.

It is a primary object of the invention to provide a squeegee whoseoperation is fast, effective and safe.

A further object of the invention is to provide a squeegee which usesthe capillary action of a soft sponge and maintains its optimumoperation by constant automatic removal of the liquid absorbed by thesponge.

A further object of the invention is to provide a squeegee which issimple in design, may be manufactured at low cost and which requiresonly a minimum of operating equipment.

A further object of the invention is to provide a squeegee which isrugged and whose effectiveness is not reduced by minor damage to itsworking surface which engages the area to be dried.

A further object of the invention is to provide a squeegee of the vacuum.type which requires only a low degree of vacuum such as that providedby a conventional aspirator.

A further object of the invention is to provide a squeegee which may bemade relatively large in area and will function to provide removal ofsurface liquid with uniform effectiveness throughout large surfaceareas.

A further object of the invention is to provide a squeegee which may beadapted for manual use or for application to and to function togetherwith other equipment such as at liquid seals in tanks where the liquidtends to seep from the tank as from resilient lip sealing means in tankwalls at points of entry and egress of film strips.

Other objects and features of the invention will more fully appear fromthe following description and will be particularly pointed out in theclaims.

To provide a better understanding of the invention specific embodimentsthereof will be described and illustrated in the accompanying drawingswherein:

FIG. 1 is a general view of an embodiment of the device in perspective.

FIG. 2 is a cross section on line 2-2 FIG. 1.

FIG. 3 is a cross section of a different embodiment of the invention.

FIG. 4 is a partial cross section showing a fixed installation of theinvention wherein the both sides of a strip type workpiece are actedupon simultaneously.

FIG. 5 is a detail cross section on line 5-5 FIG. 4.

FIG. 6 is a cross section on line 6-6 FIG. 4.

A basic form of the device is shown in FIGS. 1 and 2 wherein arectangular sponge 10 is received in a solid walled casing 11 whichcovers the sponge except for the bottom working face 12 thereof and asmall portion 13 of the sides thereof. The clearance 13 is provided toprevent contact of the casing with the workpiece 14 which may forexample be a photographic film bearing a saturated gelatine emulsionwhich is very prone to damage.

The sponge should be soft in texture and have good absorptioncharacteristics. It may be of the natural variety or a synthetic typebut should have good active capillary action. The principals of thestructure and function of the invention depend upon and are supported bythe large number of capillary tubes in the body of the sponge whichserve as channels for conveying vacuum throughout the sponge in a mannerto be described and also to convey liquid from the contacting surface 12to a waste collecting means or to recirculate the liquid back to asupply tank.

The sponge should be received snugly in the casing but not tightlyagainst the walls thereof. A tubular fitting is secured in an aperturein the top wall of the casing. The fitting is connected to an aspirator16 or other vacuum producing means. The vacuum thus applied to thesponge permeates throughout the capillary system thereof and adds itsmotivating force to the natural capillary forces acting within thesponge. Thus only a relatively small capacity vacuum generator isrequired.

For manual operation the squeegee may be supplied with a handle 17 shownin dotted lines. The device is moved over the surface of the workpiece14 and while so doing a slight pressure is applied. The resiliency ofthe sponge acts to insure perfect contact of the entire area of itsworking face 12 upon the workpiece. Thus as the device is moved over thesurface to be dried all liquid is removed leaving no skips or partialremoval areas and moreover the operation may be continuous and thesqueegee effect remains at optimum effectiveness at all times.

FIG. 3 illustrates a modified construction which substantially increasesthe operating capacity of the squeegee.\ In this form of the inventionthe sponge may be of the same construction and is received in a casinghaving an opening in its top wall to receive a vacuum connection ofspecial construction. Extending upward from the aperture in the casingis a short tubular section or conduit 18 having a plate 19 secured inits upper end and having a plurality of small apertures formed therein.Certain of these apertures 20 have secured therein small capillary tubes21 which extend down into the sponge to a substantial depth. The lowerends of these tubes may be perforated with small holes 210. Any suitablenumber of these tubes may be used. As shown in FIG. 6 there are 5 ofthem the outer tubes being bent outwardly to reach the outer portions ofthe sponge. The plate 19 also has a plurality of holes 22 shown in FIG.5 which communicate between the chamber in the tubular portion 18 and achamber 23 leading to a hose connection 24 which is coupled to a tube orhose 25 leading to a vacuum generator.

The chamber 23 communicates with a small tank 26 the upper rim 27 ofwhich is substantially in line with the plate 19. The tank 26 issupplied with a drain valve 28 through which accumulated liquid may bedrained from the tank.

In operation as the squeegee is moved over the workpiece the suctionplus the capillary action of the sponge draws the liquid into thechamber in the portion 18 of the casing and also draws liquid throughthe small tubes 21 wherein the movement of liquid is accelerated by thesmooth capillary action of the tubes themselves. Thus the liquid iscarried to the top of the plate 19 and flows by gravity into the tank 26from where it may be disposed of in any suitable manner. It will be seenin this form of the device the full volume of the chamber 23 ismaintained free of liquid and thus the full force of the vacuum actionis always at its optimum and there is substantially no reverse flow ofliquid to the sponge.

The invention in any of its embodiments may be provided with means forsecuring it to a fixed support in which case the workpiece would bemoved over the sponge surface. A fixed system for operating on bothsides of a workpiece is shown in FIG. 4, wherein a squeegee device asshown in FIG. 3 acts upon the top surface of the workpiece 14. Thisdevice is secured to a fixed support 30. The bottom face of theworkpiece is acted upon by a device similar to that shown in FIG. 3 butwithout the tank 26. The lower squeegee is operated in inverted positionand is secured toa support 31. The liquid removed from the lower surfaceof the strip 14 will flow by gravity through the vacuum fitting 32 andmove freely through the tube 33 leading to a vacuum device such as anaspirator. In this arrangement the workpiece is drawn between the twosqueegee units 4 which act simultaneously to strip the liquid from bothfaces of the workpiece 14.

It will be noted that the invention may readily be incorporated intocompletely integrated automatic systems such as in continuous processingof photographic film wherein the squeegee would be applied to the filmafter its final washing and may be a fixed station such as that shown inFIG. 4. It should be noted that the invention is well adapted forapplication to such a system using a plurality of steps in sequence suchas in processing exposed photographic materials in which case a squeegeewould be applied to each station including stripping wash watertherefrom after final washing. By so doing the various solutionsstripped from the workpiece surface could be returned to the respectiveprocessing tank without contaminating subsequent solutions. In thismanner solutions are conserved and due to the effectiveness of thedevice the quality of the final product is enhanced it being free ofwater spots, scratches and abrasions.

When using the squeegee in positions other than on the top surface of ahorizontal workpiece it is best to choose the form of the inventionwhich affords the best drainage of liquid from the squeegee. A suggestedform would be one similar to the lower squeegee in FIG. 4 or the formshown in FIGS. 1 and 2.

The sponge may also be used upon curved surfaces such as when the filmstrip or other material passes over a guide roll. In this case theoperating surface of the sponge should for best performance be shaped toconform with the roll surface. A cylindrical shaped sponge may also beused in which case means should be provided for rotation of the spongewithin a casing having a vacuum connection and designed to enclose mostof the sponge but exposing a working area thereof suflicient for bestoperation.

An important aspect of the invention resides in its facility for closecontrol and elimination of vacuum leakage in the device. This vacuumcontrol constitutes a major reason for the high efficiency andefiiectiveness of the device.

To increase the vacuum control the sponge element may be speciallyconstructed to prevent vacuum leakage at the outer surfaces 13 adjacentthe operating surface 12. To achieve this end those areas 13 and a smalladjacent portion of the sponge surface extending beneath the casing arecoated with an impervious and flexible layer such as a thin film 29 ofrubber or other material which will bond itself to the sponge and sealoff the capillaries therein but will allow complete flexibility of thesponge. This layer should be soft and quite thin. Thus the effectivevacuum acting within the sponge is sealed off down to the operatingsurface thereof despite manipulation of the sponge and moreover thesurface of the workpiece is protected from scratches and abrasions.

What is claimed is:

1. Apparatus for stripping liquid from a wetted surface comprising anabsorbing member of soft sponge-like material having a capillary cellstructure and presenting a working surface; a closely fitting gas tightcasing enclosing all but a small portion of said absorbent memberextending adjacent said working surface, a hollow liquid controllingenclosure secured to said casing having a relatively large diametervertical conduit extending from inside said casing to a position withinsaid enclosure located upon substantially a median plane between the topand bottom of said enclosure said conduit having a closure plate at theend within the enclosure, a plurality of capillary tubes in said conduitwith their upper ends secured in said plate and terminating adjacent theupper end of said vertical conduit so as to communicate with the hollowenclosure and their lower ends extending a substantial distance into thebody of said absorbing member, a liquid reservoir in said enclosurepositioned below said median plane and arranged to receive free fiow ofReferences Cited by the Examiner UNITED STATES PATENTS 3/1926Satterwhite et a1. 5/1964 Compton 15-323 X 6/1964 TOlin 15-419 X 6/1965Koppehele 15394 X 7/1965 Wisner 15-322 X FOREIGN PATENTS 6/1950 France.

ROBERT W. MICHELL, Primary Examiner.

1. APPARATUS FOR STRIPPING LIQUID FROM A WETTED SURFACE COMPRISING ANABSORBING MEMBER OF SOFT SPONGE-LIKE MATERIAL HAVING A CAPILLARY CELLSTRUCTURE AND PRESENTING A WORKING SURFACE; A CLOSELY FITTING GAS TIGHTCASING ENCLOSING ALL BUT A SMALL PORTION OF SAID ABSORBENT MEMBEREXTENDING ADJACENT SAID WORKING SURFACE, A HOLLOW LIQUID CONTROLLINGENCLOSURE SECURED TO SAID CASING HAVING A RELATIVELY LARGE DIAMETERVERTICAL CONDUIT EXTENDING FROM INSIDE SAID CASING TO A POSITION WITHINSAID ENCLOSURE LOCATED UPON SUBSTANTIALLY A MEDIAN PLANE BETWEEN THE TOPAND BOTTOM OF SAID ENCLOSURE AND CONDUIT HAVING A CLOSURE PLATE AT THEEND WITHIN THE ENCLOSURE, A PLURALITY OF CAPILLARY TUBES IN SAID CONDUITWITH THEIR UPPER ENDS SECURED IN SAID PLATE AND TERMINATING ADJACENT THEUPPER END OF SAID VERTICAL CONDUIT SO AS TO COMMUNICATE WITH THE HOLLOWENCLOSURE AND THEIR LOWER ENDS EXTENDING A SUBSTANTIAL DISTANCE INTO THEBODY OF SAID ABSORBING MEMBER, A LIQUID RESERVOIR IN SAID ENCLOSUREPOSITIONED BELOW SAID MEDIAN PLANE AND ARRANGED TO RECEIVE FREE FLOW OFLIQUID FROM SAID CONDUIT, A VACUUM CONDUIT LEADING FROM SAID ENCLOSUREABOVE SAID RESERVOIR, A VACUUM GENERATOR AND A CONNECTION THEREFROM TOSAID VACUUM CONDUIT WHEREBY FLUID FLOWING FROM SAID ABSORBING ELEMENTWILL FLOW INTO SAID RESERVOIR AND AVOID RESTRICTION TO THE VACUUM LINEAND BACKWARD FLOW OF LIQUID.